A common form of storm window in present day use includes a sash which is vertically slidable in a perimeter frame for the purpose of opening the window, the frame being mounted to the exterior or interior of the building in overlying relationship to a prime window. In one well-known type of construction the sash is a removable tilt-type sash, by which is meant that the sash can be removed from the frame for cleaning by a manual tilting operation. Specifically, each of the vertical side rails of the sash is provided near its upper end with a laterally projecting pin which rides in a vertical channel formed by the side members of the perimeter frame. The lower portion of the sash is releasably latched to the side members of the frame by means of manually operable slide bolts or the like. Upon retraction of the slide bolts the sash can be manually tilted about the axes of the pins; that is, the lower edge of the sash can be swung inwardly into the building and upwardly toward the operator. When the lower edge of the sash has been elevated a substantial distance it is a simple matter to remove the sash from the frame by lowering one side rail of the sash relative to the other so that the pins no longer reside in the channels in the frame.
It is inherent in the type of window construction summarized above that the perimeter frame does not include a fixed channel which receives the vertical side rails of the storm sash when in its closed position, as is typical for a slidable sash in a prime window. That is, if the storm sash is to be removed by tilting, the conventional frame cannot form a fixed vertical flange or web which overlies those surfaces of the sash side rails which face inwardly toward the interior of the building. The result is that there is considerable leakage of air past the sash even though weather stripping is usually provided between the laterally facing surfaces of the side rails and the frame and between the outwardly facing surfaces of the side rails and the frame. Thus there is no weather stripping along the inner faces of the sash side rails, and in addition the lack of support for these faces may permit the sash to bow slightly toward the interior of the building under the influence of wind, thereby decreasing the effectiveness of the existing weather stripping.
The window of the present invention overcomes the above-summarized disadvantages by means of special vertically movable sash retainers which provide support and sealing for a movable sash when in its down position. The sash retainers are slidable upwardly to permit removal of the sash from the retainers and from the perimeter frame. Pivot pins for the sash are not required.
A search of United States patents conducted for the purpose of determining the patentability of the present invention identified U.S. Pat. Nos. 806,105, 875,300, 2,212,221, 3,080,620, 3,105,576, 3,199,154, 3,529,381, 4,057,936, 4,151,682 and Re. 24,077. Of these, only U.S. Pat. No. 3,529,381 was regarded as being of interest. That patent discloses a single-hung storm window having a fixed upper sash and a vertically slidable lower sash which is arranged to swing or tilt inwardly toward the interior of the building for cleaning purposes. The arrangement differs from the conventional arrangement summarized above in that the slidable sash remains pivotally connected to the perimeter frame during cleaning. The slidable sash is swingable by being pivoted at its upper extremity to two vertically elongated carriages which move with the sash. When the sash is in a down position it is prevented from swinging by fixed fins or channel flanges formed by the fixed vertical side members of the frame. When the sash is moved to its up position the lower end of the sash resides above the ends of the fins so that the sash can be swung inwardly. There is no provision for removing the other sash.